The present invention relates to eyewear directed to relieving eye-related problems such as, eye muscular fatigue, headaches, and eye redness, such problems generally being identified as computer vision syndrome (xe2x80x9cCVSxe2x80x9d), or asthenopia, resulting from the use of a video display terminal. The visual science dictionary defines asthenopia as the subjective complaint of uncomfortable, painful, irritable vision.
Computers have equaled the telephone in becoming the most indispensable piece of office equipment. Because computer use is such a visually demanding task, vision problems and symptoms have become very common in today""s workplace. A survey of optometrists indicated that 10 million eye examinations are given annually in this country, primarily because of vision problems related to visual display terminals (VDT) use. This series of eye symptoms has became known as computer vision syndrome (CVS). This condition most commonly occurs when the viewing demand of the task exceeds the visual abilities of the VDT user. Almost three-quarters of people suffering from the condition are those who use corrective eyeglasses. The physiological implications for the disparity in those suffering from the condition continues to confound professionals in the field. The problem purportedly is exacerbated by the reflections produced by the lenses of the eyeglasses.
CVS is a byproduct of excessive VDT screen viewing without regard to practical visual hygiene. The symptoms of CVS can be diminished, or eliminated, if proper equipment is employed. The American Optometric Association defines CVS as that complex of eye and vision problems related to near work which are experienced during or related to computer use. The symptoms can vary, but they include eyestrain, headaches, blurred vision (distance, near, or both), dry and irritated eyes, slowed refocusing, neck ache, backache, sensitivity to light, and double vision.
The eyes are designed to be stimulated by light and to control the amount of light entering through the pupil. The predominant cause of CVS is the overwhelming extraneous light and information entering the eye when a person is using a VDT. Limiting the extraneous light coming from overhead lights can result in an immediate improvement in comfort. Controlling the amount of light that enters the eye from different directions when the operator is using the VDT will result in optimal eye relief. Limiting the light will allow the operator""s eyes to concentrate on the task at hand. As a consequence, blocking the light and information coming to the eye from different directions, except for the computer screen, makes it the single most critical parameter requiring control in order to minimize CVS.
A person engaging in near vision work is at a great risk of experiencing discomfort glare when the source of light is brighter or closer to the point of attention. This same principal applies when the light coming from behind the person, reflects on the glasses and enters the eye from a close proximity. Another significant contributor to CVS are veiling reflections, those images that are repeatedly transmitted between the computer screen and the lenses of the eyeglasses.
All segments and age ranges of society are experiencing exposure to VDTs and engaging in activities using computers such for shopping, playing games, corresponding and performing research. This increasing exposure is occurring all over the world resulting in an explosion of the numbers of individuals suffering from CVS. According to an Occupational Safety and Health Administration report published in November of 1999 the U.S. government estimates that 90% of the 70 million US workers using computers for more than 3 hours per day experience CVS in some form. In addition, a study conducted by the Department of Human Factors Engineering, University of Occupational and Environmental Health, Japan, reported that visual strain occurred as quickly as 60 minutes after commencing VDT operation.
The eyelids and tissue above the eyes contain glands which secrete tears. These tears cover the eye surface and maintain moisture for normal eye function. The tears also help to maintain the proper oxygen balance of the external eye structures and to keep the optical properties of the visual system maintained. The normal tear layer is cleaned off and refreshed by the blinking action of the eyelids. The blink reflex is one of the fastest reflexes of the body, and is present at birth; however, our blink rate varies with different activities, faster when we are very active, and slower when we are still or concentrating. Research has shown that the blink rate of VDT workers drops significantly during work at a VDT, compared with work activities prior to, and following VDT work. Possible explanations for the decreased blink rate include concentration on a task or a relatively limited range of eye movements. The size of the eye opening is related to the direction of the gaze. As a person gazes higher, the eyes open wider and the amount of tear evaporation roughly relates to the extent of the eye opening. The higher the gaze angle when viewing a VDT screen, the greater the resulting tear loss. The higher gaze angle also results in a greater percentage of incomplete blinks. Since contact lenses float on tears, people that use them are especially vulnerable to discomfort resulting from the dryness and have been instructed by the professionals not to use them during computer work.
Human eyes are stimulated by light and are capable of controlling the amount of light entering the eye through the pupil. There are conditions existing today that are foreign to the natural lighting environment, and which can cause the eye to experience an adverse reaction to light. The largest single factor in the workplace is glare. Generally speaking, there are 2 kinds of glare. Direct glare occurs, for example, when an operator sits at their computer and a light shines directly into their eyes. Reflective glare is far less perceptible and is generated by light sources from behind, above or even next to the computer operator. Reflective glare bounces needless illumination onto the user""s monitor or lenses of the eye glasses. Light from these unexpected sources is just as likely to result in CVS.
Discomfort from glare is caused primarily by great disparities in brightness in the field of view. It is much more desirable to eliminate bright sources of light from the field of view and to strive to obtain a relatively even distribution of luminaries. A person is at great risk of experiencing discomfort from glare when the source of light is brighter and closer to the point of attention. One of the primary reasons that discomfort glare is a problem for computer users is that light often leaves the overhead flourescent fixture in a wide angle, resulting in light directly entering the worker""s eyes. This is particularly a problem for computer workers because they are generally looking horizontally into the screen. Bright, open windows pose the same risks as overhead light fixtures.
A multitude of solutions to control CVS have been offered. Some of these efforts have yielded limited benefits. Some of the solutions have been contradictory, for example, dimming lights to minimize glare, and yet maintaining light bright enough to see text on a document in order to prevent strain. Also, for many companies it is nearly impossible to implement environmental solutions when large numbers of individuals operating computers sit near windows which transmit ambient light that may need to be controlled. Some individuals may want the window shades open to provide sunlight and warmth, while other computer operators in close proximity may desire to have the windows closed to limit the amount of ambient and reflected light falling upon their computer screen.
The difficulty associated with controlling the multitude of environmental factors has been the major reason why all the solutions available have not eliminated CVS. New parabolic fixtures and lighting techniques address only part of the problem. Screen filters, eye drops, software programs, wall and window coverings and ergonomic furniture lessen CVS symptoms to some degree; however, none of these techniques or products changes the lighting environment, so the number and frequency of CVS cases continues to grow.
Various types of optical apparatus have been proposed to alleviate or reduce such eyestrain by placing optical devices between the operator and the computer screen. For example U.S. Pat. No. 4,712,870 to Robinson describes a magnifying Fresnell lens which is interposed between the monitor and the operator to magnify the monitor screen image. Another such Fresnell magnifying lens and glare reduction system is disclosed in U.S. Pat. No. 4,577,928 to Brown. An anti-glare device comprising a filter screen for attachment to a cathode ray tube computer terminal display is disclosed in U.S. Pat. No. 4,253,737 to Thomsen. An adjustable lens holder for various magnifier, color tinting or anti-glare lenses is disclosed in the U.S. Pat. No. 4,529,268 to Brown.
Numerous anti-glare shields and eye shades have also been proposed for various purposes. For example, various eye shields have been proposed for drivers and pilots to reduce the glare from the sun or lights. Other eye shields have been proposed which serve as blinders to avoid distraction during various activities and for training exercises. Examples of these types of eye shields are disclosed in U.S. Pat. Nos. 2,933,734; 3,330,051; 3,308,478; 3,225,459; 5,189,445; 5,261,124 and 6,062,691. These devices do not provide adequate protection from glare and reflection from ambient light, as well as the glare from the computer terminal. Furthermore, these devices are ergonomically undesirable and create undesirable side-effects. Examples of goggles or eyeshields disclosed at U.S. Pat. Nos. 3,791,722 and 4,059,347 insufficiently limit the entry of light to the eyes and have a structure that is not conducive to the wearing of prescription glasses, and the claimed structure will result in ergonomic problems of their own as a result of the pressure needed to hold them against the face. Reiterating previously relayed statistics, nearly three-quarters of individuals suffering from CVS are wearers of eye glasses.
A principal object of the present invention is to provide suitable eyewear and a method for use by a computer user to reduce the symptoms and detrimental effects of CVS which include eyestrain, headaches, fatigue, blurring of vision, decreased productivity, dry eyes, progressive increase in the viewer""s level of nearsightedness and the like, associated with viewing of video display terminals. The eyewear limits the amount of light from all angles, except from directly forward, that reaches the eye of the user. The invention further minimizes veiled reflections and limits viewing to a central slot resulting in relaxation of tired muscle groups.
Another object of the invention is to provide accommodative eyewear to control the amount of light that enters the eye at any one time when the computer operator is using a computer, and thus controlling information to the eye from the light.
A further object of the invention is to provide accommodative eyewear to control glare generated by light sources from behind, above and next to the operator, and to eliminate glare reflecting between the VDT and corrective eye glass lenses.
A further object of the invention is to provide eyewear that will accommodate existing prescription eye glasses and that can be worn over and/or around the existing prescription eye glasses.
A further object of the invention is to provide accommodative eyewear that covers the eyes extensively limiting the field of vision to an aperture in the front of the eyewear and further limiting the amount of light that is allowed to enter and impinge upon the eye.
A further object of the invention is to provide accommodative eyewear that controls excyclorotation by limiting viewing to a central viewing area thereby relaxing tired eye muscle groups.
A further object of the invention is to provide accommodative eyewear that traps air around the eye, preventing airflow, resulting in preservation of the moisture content around the eye, thereby minimizing dryness.
A further object of the invention is to provide accommodative eyewear that exerts light pressure around the orbital area resulting in a direct massaging effect, thereby reducing eye fatigue, brain fatigue, and reducing myopia.
A further object of the invention is to provide accommodative eyewear that because of the limited field of vision associated with wearing the eyewear the user is required to move their head, neck and eyes in search of objects around their working area resulting in more frequent blinking thereby minimizing or eliminating the onset of CVS.
A further object of the invention is to improve worker productivity and well-being, reduce absenteeism and reduce visits to physicians because of CVS.
A further object of the invention is to provide accommodative eyewear leaving the ears uncovered so that the eyewear can be used simultaneously with a telephone, or with phone headsets, or over the ear phone headsets, without causing any undue pressure on the skin.
A further object of the invention is to provide eyewear that is capable of accommodating clip on anti-reflective lens, a tinted lens, a magnifying lens, a scratch resistant lens or an ultra-violet light resistant coated lens.
A further object of the invention is to provide an ergonomic eye shield for blocking the glare usually encountered by a computer operator.
The objects of the invention are basically attained by providing a housing form fitted to the face of the person, the housing having an exterior surface and a completely opaque interior surface, the housing formed to exhibit a spaced relation to the person""s face defining an interior space to accommodate a pair of prescription lenses and a prescription lens frame, the housing including a horizontal slot disposed on the level of the center of rotation of the person""s eyes. In addition, the housing has a centrally disposed nose bridge portion; an integral left and right temple arm respectively extending from the housing formed to exhibit a spaced relation to the person""s head and defining an interior space to accommodate a right and left temple arm of a pair of prescription glasses. The form fitted housing intercepts and blocks all light to the eyes of the person except light transmitted through the horizontal slot.
The objects of the invention are further attained by providing eyewear to cover the eyes of the person; the eyewear comprising a housing surrounding the person""s face, the housing having an upper and lower surface form fitting the face of the person, a horizontal slot disposed on the level of the center of rotation of the person""s eyes, a centrally disposed nose bridge portion, an exterior surface and a completely opaque interior surface. The housing is formed to exhibit a spaced relationship to the person""s face defining an interior space to accommodate a pair of prescription lenses and a prescription lens frame; the housing further having an integral left and right temple arm respectively extending from the housing formed to exhibit a spaced relation to the person""s head and defining an interior space to accommodate a right and left temple arm of a pair of prescription glasses. Then covering the eyes with the eyewear followed by viewing the computer screen and admitting light from the computer screen to the eyes through the horizontal slot, while blocking the admission to the eyes of glare.